JP2005129861A - Resin molded waterproof member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a case member which can discharge droplets and ensure the ventilation performance of a ventilating film, when the entire surface of the ventilating film covering a vent hole is unexpectedly covered with the droplets. <P>SOLUTION: In a waterproof case K formed by injection molding, devices accompanied by heat generation at the time of operation are accommodated. A through hole is formed passing through a portion of the waterproof case K from the inside to the outside, and the ventilating film S for allowing the permeation of gas but not for allowing the permeation of liquid covers the through hole, and is integrally joined thereto to form the vent hole 24. The vent hole 24 of the waterproof case K is formed so that it is in a position in use, where an outward direction perpendicular to the surface of the ventilating film S is unidentical with the downward gravitational direction. The vent hole 24 is formed with water guide grooves 27 extending from its inner wall surface 24c to the outer surface of the waterproof case K for guiding droplets W that have entered into the vent hole 24 to the outside of the waterproof case K for being discharged. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a resin-molded waterproof case member that can be ventilated between the inside and outside of a case member but is required to have a function of preventing liquid such as water droplets from entering the inside.

  Examples of the case member include a case in which electronic and / or electrical equipment is housed, for example, an ECU (Engin Control Unit) case for controlling a vehicle engine, a street light case, and the like.

  As an ECU case, there is one described in Patent Document 1. The case member is integrally attached to an end portion on the inner side of a vent hole formed in the bottom plate portion, which allows a gas to pass but prevents a liquid from passing therethrough. In this case member, if an unexpected situation occurs, for example, if a car wash or the like is performed with high-pressure water, water droplets adhere to the case member, and particularly when the water droplets that have entered the vent hole cover the entire surface of the vent film, Ventilation is impossible between inside and outside.

  In particular, when the temperature inside the case member decreases with water droplets covering the entire surface of the gas permeable membrane, the pressure inside the case member becomes negative due to this, and water droplets adhering to the entire surface of the gas permeable membrane are removed from the case member. It is possible to forcibly inhale inside. If water drops are sucked into the case member, there is a risk of causing rusting or malfunctioning of internal equipment.

In addition, if the structure has only a ventilation film attached to the inner end of a normal ventilation hole, water droplets or the like that have entered the ventilation hole and adhered to the outer membrane surface of the ventilation film will be contained in the ventilation hole. If the sum of the adhesion forces on the wall surface and the outer membrane surface of the ventilation membrane is greater than the gravity acting on the water droplets etc., the water droplets etc. in the ventilation holes will not be discharged only by gravity due to the inclination of the case member, It will be in the state which covered the ventilation membrane. Here, adhesion of water droplets or the like to the entire surface of the through-hole occurs when the adhesion force of water droplets or the like to the surface of the ventilation membrane and the inner wall surface of the ventilation hole is greater than the gravity acting on the water droplets or is balanced. it is conceivable that.
JP 2002-146087 A

  It is an object of the present invention to provide a case member capable of draining water droplets and ensuring the ventilation performance of the air-permeable membrane even if the entire surface of the air-permeable membrane that closes the air vent in an unexpected situation as described above is covered with water droplets. Yes.

  In the invention of claim 1 for solving the above-mentioned problem, a through-hole penetrating inward and outward is formed in a part of a sealed case member in which a device that generates heat during operation is accommodated, and gas is permeated. A resin injection molded case member in which a gas-permeable membrane that does not allow liquid to pass through closes the through hole and is integrally joined to form a vent hole, and the vent hole of the case member is in its use state. The outward direction perpendicular to the membrane surface of the gas permeable membrane is formed at a position that is not the same direction as the upper side in the direction of gravity, and the water that has entered the vent hole from the inner wall surface of the vent hole to the outer wall surface of the case member It is characterized in that a water guiding portion is formed to be led to the outside and drained.

  Even if water (water droplets) enters the vent hole and closes the vent membrane due to unforeseen circumstances, the vent hole is formed in the same direction as the upper side of the gravity direction, and it extends from the inner wall surface of the vent hole to the outer wall surface of the case member. Since the water guide portion is formed, the water (water droplets) is guided to the water guide portion and drained outside the case member. Therefore, the function of the vent hole is not impaired.

  The invention according to claim 2 is the invention according to claim 1, wherein the water guide portion is formed of a plurality of concave water guide grooves formed so as to continue from the inner wall surface of the vent hole toward the outside. It is characterized by.

  According to the invention of claim 2, in addition to the effects of the invention of claim 1, the water droplets that have entered the vent hole enter the water guide groove by capillary action, and then, on the outer surface side of the vent hole by gravity action. When the water droplets move and a part of the water droplets reaches the outer end of the vent hole, the water droplets fall downward from the case member due to the gravitational action. For this reason, it is difficult for water droplets to accumulate in the vent hole, and the entire surface of the vent film is prevented from being covered with water droplets. In addition, the above-described water guide groove only forms the concave water guide groove shape and the inverted ridges on the corresponding part of the molding die (the convex part for forming the vent hole) when the case member is subjected to resin injection molding. Thus, it can be easily formed simultaneously with injection molding.

  The invention according to claim 3 is the invention according to claim 2, wherein the water guide groove is radially viewed from the outside of the ventilation hole so that the distance from the axial center of the ventilation hole gradually increases toward the outside. The feature is that a plurality of lines are formed.

  According to the invention of claim 3, in addition to the function and effect of the invention of claim 2, on the inner wall surface of the vent hole, as described above, a plurality of water guide grooves are radially seen from the outside of the vent hole. Therefore, it can be used in common for case members having different mounting directions.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a tapered portion is formed in a portion near the outer surface of the vent hole so that the inner shape of the vent hole is widened. It is characterized by being.

  According to the invention of claim 4, in the invention of any one of claims 1 to 3, since the tapered portion having the above shape is formed in a portion near the outer surface side of the vent hole, it adheres to the inner wall surface of the vent hole. Thus, the water droplets that reach the outer surface side are less supported from below in the direction of gravity and are easily drained to the outside of the vent hole. In addition, to form the vent hole as described above, when the case member is molded by resin injection, the base part of the convex part for forming the vent hole in the molding die is formed in an inverted shape with the tapered part of the vent hole. It can be formed easily at the same time as injection molding.

  The invention of claim 5 is characterized in that, in the invention of claim 1, the water guide portion is a rough surface having fine irregularities formed on the inner wall surface of the vent hole.

  According to the invention of claim 5, in addition to the function and effect of the invention of claim 1, the surface of the water guide portion is roughened, and the surface area is increased due to fine irregularities. For this reason, since the water droplets that have entered the water guide portion spread, it easily flows through the water guide portion and falls toward the bottom of the case member at the outer end of the water guide portion. In addition, the roughening of the water guiding part is achieved by simply forming the roughened surface and the inverted shaped unevenness on the corresponding part of the mold (the convex part for forming the air hole) at the time of injection molding of the case member. Can be molded easily at the same time as injection molding.

  The invention of claim 6 is characterized in that, in the invention of any one of claims 1 to 5, the waterproof case member is arranged so that the membrane surface of the gas permeable membrane is substantially vertical in use. .

  According to the invention of claim 6, in addition to the function and effect of any one of the inventions of claims 1 to 5, the waterproof case member is disposed so that the membrane surface of the ventilation membrane is substantially vertical. The adhering water droplets are easily subjected to a gravitational action, and are guided to the water guiding portion and effectively drained to the outside of the vent hole.

  The invention of claim 7 is characterized in that, in any one of the inventions of claims 1 to 6, a water repellent treatment is applied to the outer membrane surface of the gas permeable membrane.

  According to the invention of claim 7, in addition to the operational effects of any one of the inventions of claims 1 to 6, water droplets that enter the ventilation hole and adhere to the ventilation film repel (extrude) outward from the ventilation film. ) Receive power. That is, since the “wetting property” on the outer side of the gas permeable membrane is reduced, the effect of preventing adhesion of water droplets to the gas permeable membrane is enhanced.

  The waterproof case member according to the present invention is formed in a position where the outward direction perpendicular to the membrane surface of the ventilation film blocking the ventilation hole is in the same direction as the upper side in the direction of gravity in the state of use. A water guide portion is formed that guides the water that has entered the ventilation hole from the wall surface to the outer wall surface of the case member and drains the water to the outside of the case member. For this reason, even if the entire surface of the gas permeable membrane is covered with water droplets due to an unforeseen situation, the water droplets are led to the outside of the air holes by the water guiding portion and drained. For this reason, even if a waterproof case member is used in an environment in which water drops may adhere to the gas permeable membrane, the original gas permeable performance of the gas permeable membrane can be ensured.

  Hereinafter, the present invention will be described in more detail with reference to the best mode for carrying out the present invention and other forms.

  1 is a perspective view of a waterproof case K according to the present invention as viewed from the bottom surface side, FIG. 2 is a cross-sectional view of the waterproof case K in which the bottom surface is horizontally arranged, and FIG. 3 is a vent hole of FIG. 4 is an enlarged cross-sectional view of a portion 24, FIG. 4 is an enlarged front view of the vent hole 24, and FIG. 5 is a portion of the vent hole 24 of the waterproof case K vertically arranged with the connector portion 14 upward in the gravity direction. It is the expansion perspective view which fractured | ruptured a part of. 1 to 5, a waterproof case K according to the present invention includes a case body 10 and a bottom lid body 20 each having a rectangular box shape. When the waterproof case K is used in a horizontal arrangement, the bottom surface of the case body 10 is open, and a wiring such as a printed circuit board, the board 1, the electronic component 2 and the like are placed in the housing space 11 inside the case body 10. After housing the necessary equipment, the bottom opening is airtightly covered with the bottom lid 20. As shown in FIG. 2, the case body 10 and the bottom cover body 20 are the same in which a rectangular frame-shaped convex portion 12 formed on the lower end surface of the case body 10 is formed on the corresponding end surface of the bottom cover body 20. In a state of being fitted in the concave portion 21 having a shape, the airtightness and the watertightness are maintained and the members are integrally joined. As an integral joining means, fixing with an adhesive / sealant having adhesiveness is generally preferred, but it is screwed or clipped via an additional sealant such as an O-ring or rubber packing. It can also be fixed by structure, vibration welding, ultrasonic welding or the like. In the present embodiment, the bottom surface portion of the case body 10 is constituted by the separate bottom lid body 20 because it is inserted from the lower side of the case body 10 rather than from the upper surface opening depending on the shape or arrangement position of the object to be accommodated. This is exemplified as a case where it is easier to arrange or cannot be inserted unless it is from the lower side, and there is an advantage that it is easy to insert an object to be stored from the lower side of the case body 10. However, in the case where the accommodation of the object to be stored in the case main body 10 can be inserted and arranged from the upper side and the insertion arrangement from the lower side is not necessary, the box-shaped case main body 10 is connected to the bottom lid 20. An integral structure may be used.

  The upper surface opening of the case main body 10 is integrally joined by the upper lid body 13 as in the case of the bottom lid body 20 while maintaining airtightness and watertightness in the same manner as the bottom lid body 20 described above. Here, in the case where the object to be stored is a device that generates heat during operation, the upper lid body 13 is preferably composed of a metal heat radiator such as plate-like aluminum in order to exhibit a heat radiation function. In this case, the upper lid 13 is in contact with the object to be accommodated through an insulating sheet having thermal conductivity. Furthermore, as shown in FIG. 2, the upper lid 13 is preferably formed with a concavo-convex portion 13 a in order to increase the surface area (outside of the case) and enhance the heat dissipation performance. If the upper lid 13 is made of a metal radiator, an excessive temperature rise and thermal expansion of the air in the case main body 10 can be suppressed due to a good heat dissipation effect. The deformation force acting on the portion where the upper lid 13 and the upper lid 13 are joined in an airtight manner is reduced, and the burden for holding the joined portion can be reduced. A cylindrical connector portion 14 is integrally formed on one side surface of the case body 10 so as to protrude outward, and the connector portion 14 is partially embedded when the case body 10 is molded. The outer part of the plurality of integrally formed metal plate terminals 3 is accommodated, and the inner part of the terminal 3 is connected to the substrate 1. An electronic component 2 is mounted on the back surface of the upper lid 13, and the electronic component 2 and the substrate 1 are connected by a connection terminal 4. In FIG. 2, reference numeral 5 denotes a protruding boss that fixes the substrate 1 to the flange portion 12 a on the upper surface of the case body 10.

  The portion of the case body 10 excluding the upper lid 13 and the bottom lid 20 are all hard such as PBT (polybutylene terephthalate), PA (nylon), PPS (polyphenylene sulfide) with or without glass fibers. It is formed of a thermoplastic resin. The bottom lid 20 can be formed by injection molding with a soft thermoplastic material such as elastomer, TPO or a soft thermosetting resin such as rubber in addition to the above materials. It has a high adhesiveness and can easily provide airtightness and watertightness.

  The bottom lid 20 has a shallow box shape, and a circular protrusion projects from the central portion of the bottom plate portion 22 toward the opening surface of the case body 10 to form a vent hole forming portion 23. Yes. A vent hole 24 having a substantially circular cross section is formed in the vent hole forming part 23 so as to penetrate in the inner and outer directions of the waterproof case K. As shown in FIG. 3, the outer side of the vent hole 24 is widened at the inner straight portion 24 a having a constant inner diameter and the outer portion of the entire thickness of the vent hole forming portion 23 at about ３. And a tapered portion 24b formed in such a tapered shape. A connecting portion (boundary portion) between the straight portion 24a and the tapered portion 24b of the vent hole 24 is formed with a smooth curved surface in order to improve the drainage of the water droplets W described later. The tapered portion 24b is formed in the vent hole 24 because water drops W adhering to a vent film S described later due to an unexpected situation easily fall down the waterproof case K along the inner wall surface 24c of the vent hole 24 (drained). This is to make it easier. A gas permeable membrane S is integrally joined to the inner end of the vent hole 24 along the inner and outer direction so as to be flush with the inner surface of the vent hole forming portion 23. The air-permeable membrane S is integrally bonded during resin injection molding of the bottom lid 20 by previously setting the bottom lid 20 on a corresponding portion of the molding die when resin injection molding the bottom lid 20. Further, the outer portion of the gas permeable membrane S in the inner / outer direction includes three membrane contact preventing portions 25 formed radially from the central portion of the gas permeable membrane S (the same position as the axial center C of the gas permeable holes). 23, the gas permeable membrane S is supported during use, and an external article is prevented from coming into direct contact with the gas permeable membrane S to protect the gas permeable membrane S. In FIG. 3, reference numeral 26 denotes a molding formed by an annular protrusion (none of which is shown) of the molding die for setting the gas permeable membrane S in a positioning state when the bottom lid 20 is resin injection molded. It is an annular groove that is one of the marks.

  The air-permeable membrane S is substantially spongy when viewed microscopically, and has an infinite number of fine pores in the irregular shape with a size of about 0.05 μm to 20 μm and facing the irregular direction. Therefore, the air permeable membrane S allows the passage of atmospheric moisture, water vapor, and smaller atmospheric gases (nitrogen gas, oxygen gas) of 0.0004 μm in size, but the size of 100 μm (approximately drizzle size) or more. It has the performance of blocking the passage of liquids such as water droplets and oil droplets and solid foreign matters such as dust. As this air-permeable membrane S, US W. L. The product name “Gore-Tex” from Gore, the product name “Micro-Tex” from Nitto Denko Co., Ltd., etc. are commercially available and can be suitably used. The materials for the above-mentioned gas permeable membranes are all polytetrafluoroethylene resin, and thicknesses of 50 μm to 200 μm are available according to the purpose, and these materials can be appropriately selected and used. .

  Further, it is preferable that a water repellent treatment is performed on the outer membrane surface of the gas permeable membrane S so as not to impair the air permeability by fluorine coating, Teflon (registered trademark) coating, or the like. As described above, when the water repellent treatment is performed on the outer membrane surface of the gas permeable membrane S, the “wetting property” of the water droplets with respect to the membrane surface is reduced, and a force to repel (push out) the water droplets to be attached is generated. The peripheral edge of the water droplet tends to be separated from the membrane surface of the gas permeable membrane S. Due to the above-described actions resulting from the water-repellent treatment, water droplets or the like are less likely to adhere to the membrane surface of the ventilation film S, and the water droplets or the like that have entered the ventilation hole 24 in cooperation with the water guide groove 27 described later are It becomes easy to drain to the outside of the vent hole 24.

  In the present embodiment, a plurality of concave water guide grooves 27 are formed radially at equal intervals along the circumferential direction from the inner wall surface 24 c of the vent hole 24 to the outer surface of the bottom plate portion 22 of the bottom lid 20. ing. That is, when the vent hole 24 is viewed from the direction perpendicular to the bottom plate portion 22 of the bottom cover body 20, the plurality of water guide grooves 27 are formed from the inner wall surface 24 c of the vent hole 24 to the bottom cover body 20 as shown in FIG. 4. The bottom plate portion 22 is formed in a radial shape with the axis C of the vent hole 24 as the center. The water guide groove 27 includes a first water guide groove portion 27 a formed on the inner wall surface 24 c of the vent hole 24 and a second water guide groove portion 27 b formed on the bottom plate portion 22 of the bottom cover body 20. And the connection part (boundary part) of each 2nd water guide groove part 27a, 27b is formed in the smooth curved surface shape so that a water drop etc. may flow smoothly and it may drain. The plurality of water guide grooves 27 are formed radially as described above when the bottom cover 20 is mounted horizontally or close to the horizontal direction around the inner wall surface 24c of the vent hole 24. This is because water droplets and the like that have entered the vent hole 24 can be easily drained through the inner wall surface 24c at any position along the direction so that the water droplets and the like that have entered the vent hole 24 can be drained. .

  The depth of the water guide groove 27 with respect to the inner wall surface 24c of the vent hole 24 and the outer surface of the bottom plate portion 22 of the bottom lid 20 is as follows. The inner wall surface 24c of the vent hole 24 is formed in a tapered shape such that the bottom surface 27c of the water guide groove 27 (first water guide groove portion 27a) is separated from the axial center C of the vent hole 24 toward the outside of the case K. Has been. In other words, the bottom surface 27c of the first water guide groove 27a is inclined so as to expand in the radial direction toward the outer surface of the bottom plate portion 22 of the bottom lid 20. The first water guide groove portion 27 a is deeper as it goes to the outside of the vent hole 24 with reference to the inner wall surface 24 c of the vent hole 24. As a result, an action of drawing water droplets or the like moving along the inner wall surface 24c of the vent hole 24 toward the outside of the vent hole 24 to the bottom surface 27c of the first water guide groove portion 27a due to capillary action occurs, and the water droplets or the like are easily drained. Become. On the other hand, in the bottom plate portion 22 of the bottom lid body 20, the depth of the water guide groove 27 (second water guide groove portion 27b) is constant.

  In order to form the tapered portion 24 b in the outer portion of the vent hole 24, or to form the water guide groove 27 from the inner wall surface 24 c of the vent hole 24 to the outer surface of the bottom plate portion 22 of the bottom lid body 20, the bottom lid body 20. It can be easily formed at the time of injection molding. That is, as shown in FIG. 6, the base portion of the convex portion 41 forming the vent hole 24 of the molding die 40 for resin injection molding of the bottom lid 20 is formed in an inverted shape of the tapered portion 24b. By forming the water guide groove 27 and the inverted protrusion 42 from the outer peripheral surface of the convex portion 41 to the molding surface of the molding die 40, it can be easily formed. 2 and 3, reference numeral 28 denotes a locking claw of the bottom cover body 20 that is locked to the outer peripheral edge of the case body 10 in a state where the bottom cover body 20 is integrally assembled to the case body 10.

  The mounting posture (arrangement posture) when the above-described waterproof case K is attached to a vehicle or the like may be different depending on the situation of the mounted portion. For example, as shown in FIG. 2, the case where the waterproof case K is attached horizontally with the bottom lid 20 positioned downward in the gravity direction will be described. In a normal use state, the general action of the gas permeable membrane S constituting the waterproof case K is as follows. Since the air permeable membrane S does not allow liquid such as rainwater droplets to pass through, the water droplets and the like do not enter the housing space 11 in which the electronic component 2 or other equipment is housed. Since the gas (gas) is permeated through the gas permeable membrane S, the electronic component 2 or other device that is the object to be accommodated in the accommodating space 11 generates heat during operation, and the air in the accommodating space 11 expands to the inside. Even if the pressure increases, the inflation gas is discharged to the outside through the gas permeable membrane S and the air holes 24, and the pressure in the accommodation space 11 is kept equal to the atmospheric pressure. Accordingly, since the pressure of the housing space 11 is prevented from being excessively increased by the gas permeable action of the gas permeable membrane S, the junction between the case body 10 and the bottom lid 20 or the junction of the gas permeable membrane S is prevented. The force accompanying the pressure increase does not act on the part, and an appropriate joined state can be maintained for a long time. On the contrary, when the operation of the equipment is stopped, the generated heat from the electronic component 2 etc. is lost, and the internal air contracts as the temperature decreases, the air is taken in from the outside through the vent hole 24 and the vent film S. Thus, the internal space 11 maintains the same pressure as the atmospheric pressure.

  However, if water droplets or the like enter the vent hole 24 due to an unexpected situation and the water droplets or the like remain on the entire outer surface of the gas permeable membrane S, the gas permeable property of the gas permeable membrane S is not achieved and the internal temperature is increased. When the pressure drops, the internal pressure becomes negative, and a force for forcibly sucking water droplets or the like adhering to the outer surface of the gas permeable membrane S is generated. However, in the waterproof case K of the present invention, a plurality of water guide grooves 27 are formed radially from the inner wall surface 24c of the vent hole 24 to the outer surface of the bottom plate portion 22 of the bottom lid body 20, so as shown in FIG. In addition, the water droplets W adhering to the outer peripheral portion of the gas permeable membrane S enter the closest water guide groove 27 (first water guide groove portion 27a) by capillary action, and along the water guide groove 27 to the outer surface side of the vent hole 24 by gravity. After moving, it moves to the water guide groove (second ventilation groove portion 27b) formed on the outer surface of the bottom plate portion 22 in a state connected to the first water guide groove portion 27a [see FIG. 8]. When a part of the water droplet W reaches the outer end of the water guide groove (second water guide groove portion 27b), it falls below the waterproof case K due to gravity (see FIG. 9). As described above, when the water droplets W adhering to the outer peripheral portion of the gas permeable membrane S enter the water guide groove 27 (first water guide groove portion 27a) by the capillary phenomenon, the contact area with the inner wall surface 24c of the vent hole 24 is increased. Further, the adhesion force of the water droplet W to the inner wall surface 24c of the vent hole 24 becomes small and the water is easily drained. By these actions, the water droplets W adhering to the gas permeable membrane S are separated from the gas permeable membrane S and drained outside the air holes 24. When the waterproof case K is mounted horizontally, the water guide groove 27 exists in the vicinity of the water droplet W adhering to the outer peripheral portion of the gas permeable membrane S at any position in the circumferential direction of the gas permeable membrane S. Therefore, the water droplets W adhering to the outer peripheral portion of the gas permeable membrane S are drained to the outside of the vent hole 24 by the action of any one of the water guide grooves 27. For this reason, since all the membrane surfaces of the gas permeable membrane S are temporarily covered with the water droplets W, they are drained immediately, so that the above-mentioned general action of the gas permeable membrane S cannot be solved.

  Further, when the waterproof case K is vertically attached with the connector portion 14 facing upward, the membrane surface of the gas permeable membrane S is disposed in the vertical direction in the direction of gravity, as shown in FIGS. 5 and 10 to 12. As shown in the figure, the water droplet W adhering to the gas permeable membrane S moves downward through the gas permeable membrane S by gravity, and then, due to capillary action, one or more water guides that are present in the vicinity and close to the vertical direction. Moves into the groove 27 (see FIG. 10), further travels down along the water guide groove 27 (see FIG. 11), and falls along the outer surface of the bottom lid 20 by the gravitational action at the lower end of the water guide groove 27. (See FIG. 12). Moreover, the part near the outer side of the vent hole 24 is formed in a taper shape, and the force to support the water droplet W reaching this part from below is reduced. Thus, when the waterproof case K is arranged vertically, the membrane surface of the gas permeable membrane S is vertical, and the one or more water guide grooves 27 connected at the lower end of the gas permeable membrane S are also perpendicular or nearly vertical. Since the gravity acts most effectively when the water droplet moves, there is an advantage that the water droplet W attached to the gas permeable membrane S is easily drained to the outside of the vent hole 24.

  Further, when the waterproof case K is vertically arranged with the connector portion 14 facing sideways, one or more water guide grooves 27 different from the above are in a vertical state or nearly vertical state, and the water guide grooves 27 are The water droplets W that have traveled and adhere to the air-permeable membrane S move downward and are drained from the air holes 24.

  In the first embodiment, the vent hole 24 is composed of an inner straight portion 24a and an outer slotted tapered portion 24b. For this reason, there exists an advantage which the drainage property of the water droplet W increases in any arrangement. However, in the present invention, the vent hole 24 may have a straight shape over its entire length, and the water guide groove 27 may be formed on the inner wall surface 24c.

  Further, the first embodiment is an example in which a plurality of water guide grooves 27 are formed from the inner wall surface 24 c of the vent hole 24 to the outer surface of the bottom plate portion 22 of the bottom lid 20 as the water guide portion. Or, in addition, even if the entire inner wall surface 24c of the vent hole 24 is formed into a rough surface having fine irregularities by, for example, a satin finish, the water flow of the water droplet W transmitted through the inner wall surface 24c of the vent hole 24 is conducted. Can increase the sex. By forming fine irregularities on the entire inner wall surface 24c of the vent hole 24, the surface area of the inner wall surface 24c is increased. As a result, the total contact area of the water droplets W with respect to the inner wall surface 24c is increased. The surface tension of W is weakened. For this reason, combined with the gravity action, the drainage performance when water droplets away from the membrane surface of the ventilation membrane S is drained through the inner wall surface 24c of the ventilation hole 24 is enhanced. Further, by forming a surfactant layer from the inner wall surface 24 c of the vent hole 24 to the outer surface of the bottom plate portion 22 of the bottom lid 20, the water droplet W collected in the vent hole 24 can be improved by increasing the fluidity of the water droplet. Drainage can be improved.

  In the first embodiment, a plurality of water guide grooves are provided radially. However, when the waterproof case K is used in a specific arrangement (for example, when the connector section 14 is vertically arranged), The water guide groove 27 formed from the inner wall surface 24 c of the vent hole 24 to the bottom plate portion 22 of the bottom lid 20 has a specific portion along the circumferential direction of the vent hole 24 (for example, the connector portion 14 on the outer periphery of the vent hole 24 and May be formed only on the opposite side).

It is the perspective view which looked at the waterproof case K which concerns on this invention from the bottom face side. It is sectional drawing of the waterproof case K by which the bottom face was horizontally arrange | positioned. FIG. 3 is an enlarged cross-sectional view of a portion of a vent hole 24 in FIG. 2. 3 is an enlarged front view of a vent hole 24. FIG. It is the expansion perspective view which fractured | ruptured a part of part of the ventilation hole 24 of the waterproof case K arranged vertically. FIG. 4 is an enlarged perspective view of a portion of the bottom lid body 20 where a mold hole 24 is formed. FIG. 6 is a schematic cross-sectional view showing a state in which a part of a water droplet W adhering to a gas permeable membrane S enters a water guide groove 27 by a capillary phenomenon when the waterproof case K is horizontally arranged. Similarly, the water droplet W that has entered the water guide groove 27 is a schematic cross-sectional view showing a state in which the water droplet W moves along the water guide groove 27. Similarly, it is a schematic cross-sectional view showing a state in which water droplets W that have entered the water guide groove 27 fall at the end of the water guide groove 27. FIG. 5 is a schematic cross-sectional view showing a state where a part of a water droplet W adhering to a gas permeable membrane S enters a water guide groove 27 by a capillary phenomenon when a waterproof case K is vertically arranged. Similarly, the water droplet W that has entered the water guide groove 27 is a schematic cross-sectional view showing a state in which the water droplet W moves along the water guide groove 27. Similarly, it is a schematic cross-sectional view showing a state in which water droplets W that have entered the water guide groove 27 fall at the end of the water guide groove 27.

Explanation of symbols

C: Axle axis
K: Waterproof case (case member)
S: Breathable membrane
W: Water drop
2: Electronic components
10: Case body (case member)
11: Containment space
20: Bottom lid (case member)
24: Ventilation hole
24a: Straight portion of vent hole
24b: Tapered portion of the vent hole
24c: Inner wall surface of the vent hole
27: Water guide groove (water guide part)

Claims (7)

A through-hole penetrating inward and outward is formed in a part of the sealed case member in which a device that generates heat during operation is accommodated, and a gas permeable membrane that allows gas to pass through but does not allow liquid to pass through plugs the through-hole and integrates it. A resin injection molded case member joined to form a vent hole,
The vent hole of the case member is formed in a position where the outward direction perpendicular to the film surface of the gas permeable membrane is in the same direction as the upper side in the direction of gravity in the usage state.
A resin-molded waterproof case member characterized in that a water-conducting portion is formed for guiding water that has entered the vent hole from the inner wall surface of the vent hole to the outer wall surface of the case member to drain the case member. 2. The resin-molded waterproof case member according to claim 1, wherein the water guide portion is formed of a plurality of concave water guide grooves formed so as to continue outward from the inner wall surface of the vent hole. 3. The resin-molded waterproof case member according to claim 2, wherein a plurality of the water guide grooves are formed in a radial shape so that a distance from the axial center of the air vent gradually increases toward the outside. . The resin-molded waterproof case according to any one of claims 1 to 3, wherein a tapered portion is formed at a portion near the outer surface side of the vent hole so that the inner shape of the vent hole is widened. Element. 2. The resin-molded waterproof case member according to claim 1, wherein the water guide portion is a rough surface having fine irregularities formed on an inner wall surface of a vent hole. The resin-molded waterproof case member according to any one of claims 1 to 5, wherein the waterproof case member is disposed so that a membrane surface of the gas permeable membrane is substantially vertical in use. The resin-molded waterproof case member according to any one of claims 1 to 6, wherein a water repellent treatment is performed on a film surface outside the gas permeable film.

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